Fine wires such as those used in high performance electronics applications are required to have a very smooth surface to perform within desired performance characteristics. Accordingly, inspection or determination of smoothness after manufacture and before the wire is utilized is highly desirable.
In the prior art the method of testing conducting surfaces, particularly fine wires, for high performance applications has been by visual inspection using a microscope. Typically a scanning electron microscope is used. Such inspection requires expensive equipment, as well as being time consuming and subject to human error as the observation and assessment is done by a human operator. Further, the human operator's assessment is a qualitative assessment based on visual observation and lacks a quantitative measurement for standardization or quantitative comparisons.
Accordingly, there is a need for a fast, non-invasive testing method for determining surface smoothness of conducting surfaces for high performance applications and preferably for a testing method that provides quantitative data reflecting surface smoothness. Additionally, in applications that involve electrical potentials on the conductive surface, there is a need to directly measure the surface emission of electrons rather than to measure the visual appearance of the surface as is typically done in the art as the visual appearance is a surrogate for the enhanced emission of electrons and it is the surface emission or leakage currents that are detrimental to performance.